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1.
Rheumatol Int ; 43(2): 265-281, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36346443

RESUMEN

Febuxostat is the drug used to treat hyperuricemia in patients with gout. Recently, the usage of Febuxostat has been controversial over the side effects in cardiovascular. The study aimed to comparatively analyze the risk of cardiovascular disease associated with febuxostat and allopurinol use in Korean patients with gout. A cohort study was conducted using national insurance claim data from the Health Insurance Review and Assessment Service (HIRA). Adult patients who were diagnosed with gout and prescribed febuxostat or allopurinol more than once from July 1, 2015, to June 30, 2018 were studied. The outcome was cardiovascular disease. Analysis was performed using Cox's proportional hazard model following 1:1 propensity score matching to estimate the hazard ratio with a 95% confidence interval. In total, 90,590 patients were defined as the final study cohort who had an average follow-up of 467 days, including 28,732 and 61,858 patients in the febuxostat and allopurinol groups, respectively. After the 1:1 propensity score matching, the risk of cardiovascular disease in the febuxostat group was significantly higher than in the allopurinol group (HR: 1.17; 95% CI: 1.10-1.24). In the sensitivity analysis, the risk of cardiovascular disease in the febuxostat group was significantly higher than in the allopurinol group (HR: 1.09; 95% CI: 1.04-1.15). However, further sensitivity analysis showed no statistically significant difference between the febuxostat group and allopurinol group after adjusting for cardiovascular disease history before the index date. Similarly, no statistically significant difference was found between the two drugs in the subgroup analysis. Febuxostat was not associated with a significantly increased risk of cardiovascular disease.


Asunto(s)
Enfermedades Cardiovasculares , Gota , Hiperuricemia , Humanos , Alopurinol/efectos adversos , Febuxostat/efectos adversos , Supresores de la Gota/efectos adversos , Enfermedades Cardiovasculares/inducido químicamente , Enfermedades Cardiovasculares/epidemiología , Estudios de Cohortes , Estudios Retrospectivos , Gota/tratamiento farmacológico , Gota/epidemiología , Gota/complicaciones , Hiperuricemia/tratamiento farmacológico , Hiperuricemia/epidemiología , Hiperuricemia/inducido químicamente , República de Corea/epidemiología
2.
Sensors (Basel) ; 23(23)2023 Nov 28.
Artículo en Inglés | MEDLINE | ID: mdl-38067858

RESUMEN

In the rapidly evolving urban advanced mobility (UAM) sphere, Vehicular Ad Hoc Networks (VANETs) are crucial for robust communication and operational efficiency in future urban environments. This paper quantifies VANETs to improve their reliability and availability, essential for integrating UAM into urban infrastructures. It proposes a novel Stochastic Petri Nets (SPN) method for evaluating VANET-based Vehicle Communication and Control (VCC) architectures, crucial given the dynamic demands of UAM. The SPN model, incorporating virtual machine (VM) migration and Edge Computing, addresses VANET integration challenges with Edge Computing. It uses stochastic elements to mirror VANET scenarios, enhancing network robustness and dependability, vital for the operational integrity of UAM. Case studies using this model offer insights into system availability and reliability, guiding VANET optimizations for UAM. The paper also applies a Design of Experiments (DoE) approach for a sensitivity analysis of SPN components, identifying key parameters affecting system availability. This is critical for refining the model for UAM efficiency. This research is significant for monitoring UAM systems in future cities, presenting a cost-effective framework over traditional methods and advancing VANET reliability and availability in urban mobility contexts.

3.
BMC Cardiovasc Disord ; 22(1): 44, 2022 02 13.
Artículo en Inglés | MEDLINE | ID: mdl-35152888

RESUMEN

BACKGROUND: Recent studies have raised concern about the association of fluoroquinolones with an increased risk of aortic aneurysm and aortic dissection. We aimed to evaluate such risk in a Korean population. METHODS: We conducted a nested case-control study using data from the National Health Insurance Service collected from 2013 to 2017 in Korea. The study cohort included patients older than 40 years and excluded patients who had used fluoroquinolones or been diagnosed with aortic aneurysm, aortic dissection, or related diseases 1 year prior to the cohort entry date. We randomly matched four controls in the risk set with each case of aortic aneurysm and aortic dissection (same sex, age, and cohort entry date). We assessed the risk of aortic aneurysm and aortic dissection from fluoroquinolones and adjusted for potential confounders using a conditional logistic regression model. RESULTS: A total of 29,638 aortic aneurysm and aortic dissection patients were identified between 2014 and 2017. The use of fluoroquinolones within a year was associated with a 10% increased risk of aortic aneurysm and aortic dissection (adjusted odds ratio: 1.10, 95% CI 1.07-1.14, p < 0.05) compared with nonusers. The risk was higher in patients who had used fluoroquinolones within 60 days (adjusted odds ratio: 1.53, 95% CI 1.46-1.62, p < 0.05). The risk of aortic aneurysm and aortic dissection positively correlated with the cumulative dose and duration of fluoroquinolone therapy (p < 0.001). CONCLUSIONS: Our study provides real-world evidence of the risk of aortic aneurysm and aortic dissection from fluoroquinolones in Korea. Patients and medical professionals should be aware that fluoroquinolones can increase the risk of aortic aneurysm and aortic dissection, which may be acerbated by high dosage and duration of use.


Asunto(s)
Antibacterianos/efectos adversos , Aneurisma de la Aorta/inducido químicamente , Aneurisma de la Aorta/epidemiología , Disección Aórtica/inducido químicamente , Disección Aórtica/epidemiología , Fluoroquinolonas/efectos adversos , Adulto , Anciano , Anciano de 80 o más Años , Disección Aórtica/diagnóstico por imagen , Aneurisma de la Aorta/diagnóstico por imagen , Estudios de Casos y Controles , Comorbilidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Farmacovigilancia , República de Corea/epidemiología , Medición de Riesgo , Factores de Riesgo , Factores de Tiempo
4.
Sensors (Basel) ; 22(24)2022 Dec 09.
Artículo en Inglés | MEDLINE | ID: mdl-36560022

RESUMEN

Text document clustering is one of the data mining techniques used in many real-world applications such as information retrieval from IoT Sensors data, duplicate content detection, and document organization. Swarm intelligence (SI) algorithms are suitable for solving complex text document clustering problems compared to traditional clustering algorithms. The previous studies show that in SI algorithms, particle swarm optimization (PSO) provides an effective solution to text document clustering problems. This PSO still needs to be improved to avoid the problems such as premature convergence to local optima. In this paper, an approach called dynamic sub-swarm of PSO (subswarm-PSO) is proposed to improve the results of PSO for text document clustering problems and avoid the local optimum by improving the global search capabilities of PSO. The results of this proposed approach were compared with the standard PSO algorithm and K-means algorithm. As for performance assurance, the evaluation metric purity is used with six benchmark data sets. The experimental results of this study show that our proposed subswarm-PSO algorithm performs best with high purity comparing the standard PSO and K-means traditional algorithms and also the execution time of subswarm-PSO comparatively takes a little less than the standard PSO algorithm.

5.
Sensors (Basel) ; 22(3)2022 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-35161968

RESUMEN

Cloud computing has been widely adopted over the years by practitioners and companies with a variety of requirements. With a strong economic appeal, cloud computing makes possible the idea of computing as a utility, in which computing resources can be consumed and paid for with the same convenience as electricity. One of the main characteristics of cloud as a service is elasticity supported by auto-scaling capabilities. The auto-scaling cloud mechanism allows adjusting resources to meet multiple demands dynamically. The elasticity service is best represented in critical web trading and transaction systems that must satisfy a certain service level agreement (SLA), such as maximum response time limits for different types of inbound requests. Nevertheless, existing cloud infrastructures maintained by different cloud enterprises often offer different cloud service costs for equivalent SLAs upon several factors. The factors might be contract types, VM types, auto-scaling configuration parameters, and incoming workload demand. Identifying a combination of parameters that results in SLA compliance directly in the system is often sophisticated, while the manual analysis is prone to errors due to the huge number of possibilities. This paper proposes the modeling of auto-scaling mechanisms in a typical cloud infrastructure using a stochastic Petri net (SPN) and the employment of a well-established adaptive search metaheuristic (GRASP) to discover critical trade-offs between performance and cost in cloud services.The proposed SPN models enable cloud designers to estimate the metrics of cloud services in accordance with each required SLA such as the best configuration, cost, system response time, and throughput.The auto-scaling SPN model was extensively validated with 95% confidence against a real test-bed scenario with 18.000 samples. A case-study of cloud services was used to investigate the viability of this method and to evaluate the adoptability of the proposed auto-scaling model in practice. On the other hand, the proposed optimization algorithm enables the identification of economic system configuration and parameterization to satisfy required SLA and budget constraints. The adoption of the metaheuristic GRASP approach and the modeling of auto-scaling mechanisms in this work can help search for the optimized-quality solution and operational management for cloud services in practice.


Asunto(s)
Algoritmos , Nube Computacional , Carga de Trabajo
6.
Sensors (Basel) ; 21(9)2021 May 04.
Artículo en Inglés | MEDLINE | ID: mdl-34064491

RESUMEN

Text document clustering refers to the unsupervised classification of textual documents into clusters based on content similarity and can be applied in applications such as search optimization and extracting hidden information from data generated by IoT sensors. Swarm intelligence (SI) algorithms use stochastic and heuristic principles that include simple and unintelligent individuals that follow some simple rules to accomplish very complex tasks. By mapping features of problems to parameters of SI algorithms, SI algorithms can achieve solutions in a flexible, robust, decentralized, and self-organized manner. Compared to traditional clustering algorithms, these solving mechanisms make swarm algorithms suitable for resolving complex document clustering problems. However, each SI algorithm shows a different performance based on its own strengths and weaknesses. In this paper, to find the best performing SI algorithm in text document clustering, we performed a comparative study for the PSO, bat, grey wolf optimization (GWO), and K-means algorithms using six data sets of various sizes, which were created from BBC Sport news and 20 newsgroups. Based on our experimental results, we discuss the features of a document clustering problem with the nature of SI algorithms and conclude that the PSO and GWO SI algorithms are better than K-means, and among those algorithms, the PSO performs best in terms of finding the optimal solution.

7.
Sensors (Basel) ; 21(18)2021 Sep 17.
Artículo en Inglés | MEDLINE | ID: mdl-34577460

RESUMEN

The aggressive waves of ongoing world-wide virus pandemics urge us to conduct further studies on the performability of local computing infrastructures at hospitals/medical centers to provide a high level of assurance and trustworthiness of medical services and treatment to patients, and to help diminish the burden and chaos of medical management and operations. Previous studies contributed tremendous progress on the dependability quantification of existing computing paradigms (e.g., cloud, grid computing) at remote data centers, while a few works investigated the performance of provided medical services under the constraints of operational availability of devices and systems at local medical centers. Therefore, it is critical to rapidly develop appropriate models to quantify the operational metrics of medical services provided and sustained by medical information systems (MIS) even before practical implementation. In this paper, we propose a comprehensive performability SRN model of an edge/fog based MIS for the performability quantification of medical data transaction and services in local hospitals or medical centers. The model elaborates different failure modes of fog nodes and their VMs under the implementation of fail-over mechanisms. Sophisticated behaviors and dependencies between the performance and availability of data transactions are elaborated in a comprehensive manner when adopting three main load-balancing techniques including: (i) probability-based, (ii) random-based and (iii) shortest queue-based approaches for medical data distribution from edge to fog layers along with/without fail-over mechanisms in the cases of component failures at two levels of fog nodes and fog virtual machines (VMs). Different performability metrics of interest are analyzed including (i) recover token rate, (ii) mean response time, (iii) drop probability, (iv) throughput, (v) queue utilization of network devices and fog nodes to assimilate the impact of load-balancing techniques and fail-over mechanisms. Discrete-event simulation results highlight the effectiveness of the combination of these for enhancing the performability of medical services provided by an MIS. Particularly, performability metrics of medical service continuity and quality are improved with fail-over mechanisms in the MIS while load balancing techniques help to enhance system performance metrics. The implementation of both load balancing techniques along with fail-over mechanisms provide better performability metrics compared to the separate cases. The harmony of the integrated strategies eventually provides the trustworthiness of medical services at a high level of performability. This study can help improve the design of MIS systems integrated with different load-balancing techniques and fail-over mechanisms to maintain continuous performance under the availability constraints of medical services with heavy computing workloads in local hospitals/medical centers, to combat with new waves of virus pandemics.


Asunto(s)
Nube Computacional , Sistemas de Computación , Simulación por Computador , Humanos , Sistemas de Información , Recompensa
8.
Int J Dent Hyg ; 19(1): 29-38, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-32794341

RESUMEN

OBJECTIVES: We performed a systematic review of studies that assessed the efficacy of mobile health care in patients undergoing fixed orthodontic treatment, in an attempt to obtain contemporary evidence on the clinical impact of mobile health care on the patients' oral health and orthodontic treatment outcomes. METHODS: A systematic literature search was conducted using the PRISMA guidelines. We performed a comprehensive search using multiple databases (Cochrane Library, MEDLINE, EMBASE, Scopus, Google Scholar and Web of Science) with no restrictions on the language of publication or publication status up until 23 April 2019 to identify eligible studies. RESULTS: We included 11 unique studies. In this review, 9 of the 11 selected studies showed positive effects of mobile healthcare intervention, which resulted in reduced scores of oral hygiene and periodontal indices and white-spot lesions, as well as decreased duration of treatment, sagittal distance and intensity of self-reported pain. CONCLUSIONS: Mobile health care can be utilized as an adjuvant intervention to improve treatment outcomes in patients undergoing fixed orthodontic treatment. Oral healthcare experts should consider novel interventions using mobile devices in addition to the conventional mode of intervention.


Asunto(s)
Telemedicina , Envío de Mensajes de Texto , Humanos , Higiene Bucal
9.
BMC Health Serv Res ; 19(1): 299, 2019 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-31077202

RESUMEN

BACKGROUND: Patient safety culture is a core factor in increasing patient safety, is related to the quality of medical service, and can lower the risk of patient safety accidents. However, in dentistry, research has previously focused mostly on reporting of patient safety accidents. Dental professionals' patient safety culture must therefore first be assessed, and related factors analyzed to improve patient safety. METHODS: This cross-sectional study completed a survey on 377 dental hygienists working in dental settings. To assess patient safety culture, we used a survey with proven validity and reliability by translating the Hospital Survey on Patient Safety Culture (HSOPS) developed by Agency for Healthcare Research and Quality (AHRQ) into Korean. Response options on all of the items were on 5-point Likert-type scales. SPSS v21 was used for statistical analysis. The relationships between workplace factors and patient safety culture were examined using t-tests and one-way analysis of variance (ANOVA) tests(p < 0.05). RESULTS: The work environment of dental hygienists has a close relationship with patient safety. Dental hygienists working ≥40 h/week in Korea had a significantly lower for patient safety grade than those working < 40 h/week. When the number of patients per day was less than 8, the safety level of patients was significantly higher. And significant differences were found depending on institution type, institution size. CONCLUSIONS: In order to establish high-quality care and patient safety system practical policies must be enacted. In particular, assurance in the quality of work environment such as sufficient staffing, appropriate work hours, and enough rest must first be realized before patient safety culture can easily be formed.


Asunto(s)
Higienistas Dentales , Seguridad del Paciente , Administración de la Seguridad , Lugar de Trabajo , Actitud del Personal de Salud , Estudios Transversales , Femenino , Administradores de Instituciones de Salud/psicología , Humanos , Masculino , Calidad de la Atención de Salud , Reproducibilidad de los Resultados , República de Corea , Encuestas y Cuestionarios
10.
Int J Mol Sci ; 20(14)2019 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-31319552

RESUMEN

Acne is an inflammatory skin disorder in puberty with symptoms including papules, folliculitis, and nodules. Propionibacterium acnes (P. acnes) is the main anaerobic bacteria that cause acne. It is known to proliferate within sebum-blocked skin hair follicles. P. acnes activates monocytic cell immune responses to induce the expression of proinflammatory cytokines. Although the anti-inflammatory function of the Laurus nobilis (L. nobilis) extract (LNE) on several immunological disorders have been reported, the effect of LNE in P. acnes-mediated skin inflammation has not yet been explored. In the present study, we examined the ability of the LNE to modulate the P. acnes-induced inflammatory signaling pathway, and evaluated its mechanism. LNE significantly suppressed the expression of P. acnes-mediated proinflammatory cytokines, such as IL-1ß, IL-6, and NLRP3. We also found that LNE inhibited the inflammatory transcription factor NF-κB in response to P. acnes. In addition, eucalyptol, which is the main constituent of LNE, consistently inhibited P. acnes-induced inflammatory signaling pathways. Moreover, LNE significantly ameliorated P. acnes-induced inflammation in a mouse model of acne. We suggest for the first time that LNE hold therapeutic value for the improvement of P. acnes-induced skin inflammation.


Asunto(s)
Acné Vulgar/tratamiento farmacológico , Antiinflamatorios/farmacología , Eucaliptol/farmacología , Infecciones por Bacterias Grampositivas/tratamiento farmacológico , Laurus/química , Extractos Vegetales/farmacología , Propionibacterium acnes/crecimiento & desarrollo , Acné Vulgar/metabolismo , Acné Vulgar/microbiología , Acné Vulgar/patología , Animales , Antiinflamatorios/química , Línea Celular , Eucaliptol/química , Infecciones por Bacterias Grampositivas/metabolismo , Infecciones por Bacterias Grampositivas/microbiología , Infecciones por Bacterias Grampositivas/patología , Inflamación/tratamiento farmacológico , Inflamación/metabolismo , Inflamación/microbiología , Inflamación/patología , Ratones , Extractos Vegetales/química
11.
Small ; 13(18)2017 05.
Artículo en Inglés | MEDLINE | ID: mdl-28294569

RESUMEN

Interface enhanced magnetism attracts much attention due to its potential use in exploring novel structure devices. Nevertheless, the magnetic behavior at interfaces has not been quantitatively determined. In this study, abnormal magnetic moment reduction is observed in La0.7 Sr0.3 MnO3 (LSMO)/BiFeO3 (BFO) superlattices, which is induced by ferromagnetic (FM)/antiferromagnetic (AFM) coupling in the interface. With reduced repetition of the superlattice's unit cell [(LSMO)n /(BFO)n ]60/n (n = 1, 2, 5, 10) on a SrTiO3 substrate, magnetic moment reduction from 25.5 emu cc-1 ([(LSMO)10 /(BFO)10 ]6 ) to 1.5 emu cc-1 ([(LSMO)1 /(BFO)1 ]60 ) is obtained. Ab initio simulations show that due to the different magnetic domain formation energies, the magnetic moment orientation tends to be paramagnetic in the FM/AFM interface. The work focuses on the magnetic domain formation energy and provides a pathway to construct artificial heterostructures that can be an effective way to tune the magnetic moment orientation and control the magnetization of ultrathin films.

12.
Int J Syst Evol Microbiol ; 67(8): 3083-3088, 2017 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-28829033

RESUMEN

A Gram-stain-negative, strictly aerobic bacterium, designated R1-4T, was isolated from soil from a military shooting range in the Republic of Korea. Cells were non-motile short rods, oxidase-positive and catalase-negative. Growth of R1-4T was observed at 15-45 °C (optimum, 30 °C) and pH 6.0-9.0 (optimum, pH 7.0). R1-4T contained summed feature 8 (comprising C18 : 1ω7c/C18 : 1ω6c), summed feature 3 (comprising C16 : 1ω7c/C16 : 1ω6c), cyclo-C19 : 0ω8c and C16 : 0 as the major fatty acids and ubiquinone-10 as the sole isoprenoid quinone. Phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol, sphingoglycolipid, phosphatidylcholine, an unknown glycolipid and four unknown lipids were detected as polar lipids. The major polyamine was spermidine. The G+C content of the genomic DNA was 64.4 mol%. The results of phylogenetic analysis based on 16S rRNA gene sequences indicated that R1-4T formed a tight phylogenetic lineage with Novosphingobium sediminicola HU1-AH51T within the genus Novosphingobium. R1-4T was most closely related to N. sediminicola HU1-AH51T with a 98.8 % 16S rRNA gene sequence similarity. The DNA-DNA relatedness between R1-4T and the type strain of N. sediminicola was 37.8±4.2 %. On the basis of phenotypic, chemotaxonomic and molecular properties, it is clear that R1-4T represents a novel species of the genus Novosphingobium, for which the name Novosphingobium humi sp. nov. is proposed. The type strain is R1-4T (=KACC 19094T=JCM 31879T).


Asunto(s)
Filogenia , Microbiología del Suelo , Sphingomonadaceae/clasificación , Técnicas de Tipificación Bacteriana , Composición de Base , ADN Bacteriano/genética , Ácidos Grasos/química , Armas de Fuego , Hibridación de Ácido Nucleico , Fosfolípidos/química , ARN Ribosómico 16S/genética , República de Corea , Análisis de Secuencia de ADN , Espermidina/química , Sphingomonadaceae/genética , Sphingomonadaceae/aislamiento & purificación , Ubiquinona/química
13.
Rural Remote Health ; 17(3): 4164, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28918642

RESUMEN

INTRODUCTION: The purpose of this study was to analyze the effects of an oral health care program administered at rural public health subcenters on oral hygiene status and bleeding on probing (BOP) scores among Korean rural residents older than 40 years. METHODS: Residents older than 40 years living in two rural areas were allocated randomly by order of visit into an intervention group (n=23) and control group (n=23). Changes in plaque and BOP score were analyzed between the groups using repeated-measures ANOVA. Hierarchical multiple regression analysis was conducted to identify factors affecting changes in BOP score. RESULTS: The BoP score decreased by 22.87 in the intervention group and 0.27 in the control group between baseline and the eighth week (p<0.001). Multiple regression analysis showed that the change in BoP score (ΔBoP score) increased significantly with an increase in the reduction of the plaque (PHP) index (ΔPHP index) (t=-2.174, p<0.05) and increased significantly more in the intervention group than in the control group (t=2.143, p<0.05). CONCLUSIONS: Professional care and continuous oral health education for 8 weeks prior to scaling among adults older than 40 years living in rural environments resulted in a change in oral health behaviors and a substantial reduction in gingival bleeding.


Asunto(s)
Atención Odontológica/organización & administración , Enfermedades de las Encías/prevención & control , Educación en Salud/organización & administración , Higiene Bucal/métodos , Población Rural , Anciano , Femenino , Conductas Relacionadas con la Salud , Conocimientos, Actitudes y Práctica en Salud , Humanos , Masculino , Persona de Mediana Edad , Índice Periodontal , República de Corea , Factores Socioeconómicos
14.
J Cell Biochem ; 115(10): 1752-61, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24819721

RESUMEN

Abnormal proliferation of vascular smooth muscle cells (VSMCs) is a common feature of disease progression in atherosclerosis. Cell proliferation is regulated by cell cycle regulatory proteins. MicroRNAs (miR) have been reported to act as important gene regulators and play essential roles in the proliferation and migration of VSMCs in a cardiovascular disease. However, the roles and mechanisms of miRs in VSMCs and neointimal formation are far from being fully understood. In this study, cell cycle-specific cyclin D1 was found to be a potential target of miR-365 by direct binding. Through an in vitro experiment, we showed that exogenous miR-365 overexpression reduced VSMC proliferation and proliferating cell nuclear antigen (PCNA) expression, while miR-365 was observed to block G1/S transition in platelet-derived growth factor-bb (PDGF-bb)-induced VSMCs. In addition, the proliferation of VSMCs by various stimuli, including PDGF-bb, angiotensin II (Ang II), and serum, led to the downregulation of miR-365 expression levels. The expression of miR-365 was confirmed in balloon-injured carotid arteries. Taken together, our results suggest an anti-proliferative role for miR-365 in VSMC proliferation, at least partly via modulating the expression of cyclin D1. Therefore, miR-365 may influence neointimal formation in atherosclerosis patients.


Asunto(s)
Aterosclerosis/patología , Ciclina D1/biosíntesis , MicroARNs/genética , Músculo Liso Vascular/crecimiento & desarrollo , Neointima/genética , Angiotensina II/farmacología , Animales , Becaplermina , Arterias Carótidas/metabolismo , Traumatismos de las Arterias Carótidas/metabolismo , División Celular/genética , Movimiento Celular/genética , Proliferación Celular/genética , Células Cultivadas , Regulación hacia Abajo , MicroARNs/biosíntesis , Músculo Liso Vascular/citología , Antígeno Nuclear de Célula en Proliferación/biosíntesis , Unión Proteica , Proteínas Proto-Oncogénicas c-sis/farmacología , Proteínas de Unión al ARN , Ratas , Puntos de Control de la Fase S del Ciclo Celular/genética
15.
Adv Funct Mater ; 24(47): 7478-7487, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26213531

RESUMEN

Highly strained films of BiFe0.5Mn0.5O3 (BFMO) grown at very low rates by pulsed laser deposition were demonstrated to exhibit both ferrimagnetism and ferroelectricity at room temperature and above. Magnetisation measurements demonstrated ferrimagnetism (TC ∼ 600K), with a room temperature saturation moment (MS ) of up to 90 emu/cc (∼ 0.58 µB /f.u) on high quality (001) SrTiO3. X-ray magnetic circular dichroism showed that the ferrimagnetism arose from antiferromagnetically coupled Fe3+ and Mn3+. While scanning transmission electron microscope studies showed there was no long range ordering of Fe and Mn, the magnetic properties were found to be strongly dependent on the strain state in the films. The magnetism is explained to arise from one of three possible mechanisms with Bi polarization playing a key role. A signature of room temperature ferroelectricity in the films was measured by piezoresponse force microscopy and was confirmed using angular dark field scanning transmission electron microscopy. The demonstration of strain induced, high temperature multiferroism is a promising development for future spintronic and memory applications at room temperature and above.

16.
Opt Express ; 22(22): 27542-52, 2014 Nov 03.
Artículo en Inglés | MEDLINE | ID: mdl-25401901

RESUMEN

Visualizing the electromagnetic field transformation inside a microwave mode conversion region has been considered to be only realizable by simulation studies. For the first time, we present a comprehensive experimental observation of the electric field transformation occurring inside a metallic waveguide TE(01)-to-TE(02) mode converter. An efficient electro-optic (EO) probe and its associated probing system were used for measuring the electric field pattern in the external near-field region as well as in the internal and penetrated region of the mode converter. Utilizing the optically measured field patterns at the aperture of the mode converter, the conversion performance from the TE(01) mode to the TE(02) mode can be also evaluated. Experimentally measured field patterns near the apertures show excellent agreement with simulation data. The mode conversion to the next higher-order mode (TE(01) to TE(02)) was experimentally demonstrated with phase-stabilized and field-animated post processing. The presented in situ endoscopic photonic measurement technique for the field evolution inside a semi-enclosed structure could be used for visually inspecting manufacturing errors in fabricated structures, and could be of great interest for research on higher-order mode formation and transmission.

17.
J Nanosci Nanotechnol ; 14(2): 2001-11, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24749469

RESUMEN

Unlike conventional two-dimensional (2D) planar structures, signal or power is supplied through through-silicon via (TSV) in three-dimensional (3D) integration technology to replace wires for binding the chip/wafer. TSVs have becomes an essential technology, as they satisfy Moore's law. This 3D integration technology enables system and sensor functions at a nanoscale via the implementation of a highly integrated nano-semiconductor as well as the fabrication of a single chip with multiple functions. Thus, this technology is considered to be a new area of development for the systemization of the nano-bio area. In this review paper, the basic technology required for such 3D integration is described and methods to measure the bonding strength in order to measure the void occurring during bonding are introduced. Currently, CMOS image sensors and memory chips associated with nanotechnology are being realized on the basis of 3D integration technology. In this paper, we intend to describe the applications of high-performance nano-biosensor technology currently under development and the direction of development of a high performance lab-on-a-chip (LOC).


Asunto(s)
Diseño Asistido por Computadora , Electrónica/instrumentación , Nanotecnología/instrumentación , Procesamiento de Señales Asistido por Computador/instrumentación , Transductores , Diseño de Equipo , Análisis de Falla de Equipo , Integración de Sistemas
18.
J Nanosci Nanotechnol ; 14(1): 924-31, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24730309

RESUMEN

Scanning probe microscopy (SPM) is considered one of the most powerful tools for nanoscale studies that are becoming increasingly important, and SPM has shown rapid development. Atomic force microscopy (AFM), in particular, is the widely used SPM system. SPM, and especially AFM, has been used as a new measuring tool for phenomena that were earlier difficult to prove because of the limitations of earlier systems. In addition SPM allows acquiring nanoscale resolution images of the surface of materials. New applications are constantly being developed for SPM, and it is now used actively in material sciences and biological fields. The most important reason why SPM has attracted attention in the biological field is because it can be used in liquids as well. This allows the study of live cells and various other systems in nanoscale. Recently, there have been many advances in nanoscale studies, such as studies of cell interactions, cell changes according to environmental changes, and development of biosensors. This review is focused on applications in nanodevices, as well as on specific biological applications to discuss the development and opportunities of SPM in the biological field.


Asunto(s)
Fenómenos Fisiológicos Celulares , Separación Celular/instrumentación , Electrónica/instrumentación , Micromanipulación/instrumentación , Microscopía de Fuerza Atómica/instrumentación , Nanotecnología/instrumentación , Mapeo de Interacción de Proteínas/instrumentación , Diseño de Equipo , Análisis de Falla de Equipo
19.
Proc Natl Acad Sci U S A ; 108(1): 296-301, 2011 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-21173226

RESUMEN

Despite the safety and feasibility of mesenchymal stem cell (MSC) therapy, an optimal cell type has not yet emerged in terms of electromechanical integration in infarcted myocardium. We found that poor to moderate survival benefits of MSC-implanted rats were caused by incomplete electromechanical integration induced by tissue heterogeneity between myocytes and engrafted MSCs in the infarcted myocardium. Here, we report the development of cardiogenic cells from rat MSCs activated by phorbol myristate acetate, a PKC activator, that exhibited high expressions of cardiac-specific markers and Ca(2+) homeostasis-related proteins and showed adrenergic receptor signaling by norepinephrine. Histological analysis showed high connexin 43 coupling, few inflammatory cells, and low fibrotic markers in myocardium implanted with these phorbol myristate acetate-activated MSCs. Infarct hearts implanted with these cells exhibited restoration of conduction velocity through decreased tissue heterogeneity and improved myocardial contractility. These findings have major implications for the development of better cell types for electromechanical integration of cell-based treatment for infarcted myocardium.


Asunto(s)
Tratamiento Basado en Trasplante de Células y Tejidos/métodos , Células Madre Mesenquimatosas/metabolismo , Contracción Miocárdica/fisiología , Infarto del Miocardio/terapia , Miocitos Cardíacos/fisiología , Análisis de Varianza , Animales , Western Blotting , Conexina 43/metabolismo , Citocinas/inmunología , Electrocardiografía , Ensayo de Inmunoadsorción Enzimática , Técnica del Anticuerpo Fluorescente , Etiquetado Corte-Fin in Situ , Isoproterenol/farmacología , Masculino , Trasplante de Células Madre Mesenquimatosas/métodos , Células Madre Mesenquimatosas/citología , Contracción Miocárdica/efectos de los fármacos , Miocitos Cardíacos/citología , Norepinefrina/metabolismo , Ratas , Ratas Sprague-Dawley , Receptores Adrenérgicos/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Acetato de Tetradecanoilforbol/metabolismo
20.
Nano Lett ; 13(12): 5886-90, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24283467

RESUMEN

La2CoMnO6 (LcmO)-ZnO nanocomposite thin films grown on SrTiO3 and Nb-SrTiO3 (001) are investigated. The films grow in the form of self-assembled epitaxial vertically aligned structures. We show that, at 120 K, an electric field applied across the nanocomposite reversibly alters magnetic properties of LcmO. The effect is consistent with charge-mediated coupling between magnetism and an electric field that can be induced by changes in ion valences.


Asunto(s)
Imanes/química , Nanocompuestos/química , Óxido de Zinc/química , Cristalización , Campos Electromagnéticos , Óxidos/química , Estroncio/química , Propiedades de Superficie , Titanio/química
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